Bikini-clad Jessica Simpson flashes her baby bump in Hawaii

Jessica Simpson was pretty much keeping her body under wraps before her baby-on-board announcement came on Christmas Day, but now it looks as if all bets are off. She posted a picture Sunday showing off a whole lot of pregnant-again Jessica.

"Bumpin' and Proud!," the second-time mother-to-be wrote on Twitter, referencing her growing baby bump, displayed prominently in the bikini photo taken while she's on vacation in Hawaii with fiance Eric Johnson and their daughter, Maxwell.

Also along on the trip: mom Tina, sister Ashlee, and Ashlee’s son Bronx, according to ABC News.

Simpson confirmed her pregnancy last week in another Twitter photo, showing Maxwell on the beach with "Big sis" written in the sand beneath her.

The "Fashion Star" mentor has been busy with the camera while on vacation — and not shy about flaunting her bod. On Thursday, she posted a shot of herself in a cover-up that wasn't covering up all that much, in the bosom department.